Windshield Wipers
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From: Australia
A problem in the self park area. Dont specifically know about 928 wipers, but other self-parkers I have looked at have the wipers always powered, and the on switch makes earth/ground. Bypassing the stalk switch, there is commonly a separate earth path inside the wiper case (to keep the motor running), which is interrupted when the wipers reach the park position and a cam opens these contacts. Sounds like the internal contact has failed in some fashion. I would see if any of the wires coming out of the unit are damaged/broken/disconnected (especially a ground) before removing and opening the unit. Then again some !@#$%^&* wipers implement the park by applying +12V to BOTH sides of the motor (0V potential), which must enable them to save a few inches of wire?
jp 83 Euro S AT 49k
jp 83 Euro S AT 49k
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From: NJ but from Boston
AJK & JP,
On my early 86S the wipers won't turn off once activated. The wiper control stalk has no effect on wipers except turing them on?
This new malady just started. I will switch out the wiper relay to see if that's the problem.
RDS
On my early 86S the wipers won't turn off once activated. The wiper control stalk has no effect on wipers except turing them on?
This new malady just started. I will switch out the wiper relay to see if that's the problem.
RDS
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Has the motor been replaced on the mechanism? The motor just goes around and around. If it's stopping at the same place, it sounds to me like the shaft isn't indexed to the mechanism correctly.
RDS - Could be a bad relay.
RDS - Could be a bad relay.
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From: Dearborn Heights, MI
With the wipers off; at the wiper motor, disconnect the linkage.
Turn the motor shaft so when you reconnect the linkage, its at the farthest point toward the passenger side fender. This is the parked position which is the lowest point.
Turn the motor shaft so when you reconnect the linkage, its at the farthest point toward the passenger side fender. This is the parked position which is the lowest point.
Captain Obvious
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From: Cambridge, Ontario, Canada
Originally Posted by GlenL
Has the motor been replaced on the mechanism? The motor just goes around and around. If it's stopping at the same place, it sounds to me like the shaft isn't indexed to the mechanism correctly.
RDS - Could be a bad relay.
RDS - Could be a bad relay.
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From: NJ but from Boston
Glen,
thanks. I just ordered the relay.
Does any one else have that horrible creaking/whirring mechanical noise coming from the wiper motor area when the wipers are activated.
Also why do the wiper pivot arms always end up chewing up the plastic rain cowl cover over the wiper motor ?.
I just replaced my wiper motor. The first one siezed when the wiper pivot arms got stuck on the plastic rain cowl.
Thanks RDS
thanks. I just ordered the relay.
Does any one else have that horrible creaking/whirring mechanical noise coming from the wiper motor area when the wipers are activated.
Also why do the wiper pivot arms always end up chewing up the plastic rain cowl cover over the wiper motor ?.
I just replaced my wiper motor. The first one siezed when the wiper pivot arms got stuck on the plastic rain cowl.
Thanks RDS
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From: Phoenix AZ
RDS,
The wiper relay only affects the intermittent mode. All the normal wiper functions are driven directly by the wiper switch.
The intermittent wiper relay is triggered by intermittent mode and wash mode (it does the 3 wipe thing). Rather than replace the relay (they are expensive) I'd remove it and see if your problem goes away. Other than intermittent mode & 3 wipes with your wash pull - you won't lose any wiper functionality. If it works OK without the relay - change it. however if its the same without the relay this won't help.
If you do need to change the relay don't get a Porsche replacement! Do the digital wiper upgrade using a VW wiper relay (direct plug in replacement). You'll thank me - its hugely better functionally - its also cheaper than a new Porsche relay search the archives for "intermittent wipers" for more details.
Alan
The wiper relay only affects the intermittent mode. All the normal wiper functions are driven directly by the wiper switch.
The intermittent wiper relay is triggered by intermittent mode and wash mode (it does the 3 wipe thing). Rather than replace the relay (they are expensive) I'd remove it and see if your problem goes away. Other than intermittent mode & 3 wipes with your wash pull - you won't lose any wiper functionality. If it works OK without the relay - change it. however if its the same without the relay this won't help.
If you do need to change the relay don't get a Porsche replacement! Do the digital wiper upgrade using a VW wiper relay (direct plug in replacement). You'll thank me - its hugely better functionally - its also cheaper than a new Porsche relay search the archives for "intermittent wipers" for more details.
Alan
Last edited by Alan; Nov 4, 2005 at 01:23 PM.
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From: Phoenix AZ
RDS,
The plastic cowl usually does not get installed correctly (mechanics etc) and hangs down into the range of motion of the wipers - once the actualting arms get hold of it it gets ripped up pretty quick and never will install correctly again. The front lip under the windscreen has little clips (probably about 4-5) across its width and the long lip at the back of the cowl is supposed to slip between these. They are hard to see - fiddly to engage and if you didn't know they were there you just stuff the cowl under as best you can - then it droops!
First make sure these clips are there and adjusted to be a snug fit.... if needed buy a new cowl - an old cracked & chewed up one will never fit very well (~$75 ouch). carefully fit the cowl at the windscreen side first and under the rubber seal on the engine bulkhead side. New ones fit remarkably well... (my wallet empty of $75 knows all about this - most expensive piece of flimsy plastic I ever bought).
Every time you have the car serviced - check the cowl is on right before you run the wipers.....
Alan
The plastic cowl usually does not get installed correctly (mechanics etc) and hangs down into the range of motion of the wipers - once the actualting arms get hold of it it gets ripped up pretty quick and never will install correctly again. The front lip under the windscreen has little clips (probably about 4-5) across its width and the long lip at the back of the cowl is supposed to slip between these. They are hard to see - fiddly to engage and if you didn't know they were there you just stuff the cowl under as best you can - then it droops!
First make sure these clips are there and adjusted to be a snug fit.... if needed buy a new cowl - an old cracked & chewed up one will never fit very well (~$75 ouch). carefully fit the cowl at the windscreen side first and under the rubber seal on the engine bulkhead side. New ones fit remarkably well... (my wallet empty of $75 knows all about this - most expensive piece of flimsy plastic I ever bought).
Every time you have the car serviced - check the cowl is on right before you run the wipers.....
Alan
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Originally Posted by RDS928S
... Does any one else have that horrible creaking/whirring mechanical noise coming from the wiper motor
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From: Phoenix AZ
Rich - yes wipe switch = RHS main stalk.
On mine it has 3 latched wiper speed position upward (you may have 2) + wipe once w/flick-up and intermittent down. Push for headlight wash, pulls for windscreen wash (+ wipe x 3).
All the upward wipe positions are direct drive from the switch and should work without a relay.
Yep agree with Heinrich - 928 wipers are a tad on the noisy side.
Must say Mercedes did a much nicer job with their single wiper design - I love those! Since AFAIK they are still the only ones doing (?) it they must have good patent protection! It may not be totally silent but just watching it takes you mind off the noise!
Alan.
On mine it has 3 latched wiper speed position upward (you may have 2) + wipe once w/flick-up and intermittent down. Push for headlight wash, pulls for windscreen wash (+ wipe x 3).
All the upward wipe positions are direct drive from the switch and should work without a relay.
Yep agree with Heinrich - 928 wipers are a tad on the noisy side.
Must say Mercedes did a much nicer job with their single wiper design - I love those! Since AFAIK they are still the only ones doing (?) it they must have good patent protection! It may not be totally silent but just watching it takes you mind off the noise!
Alan.
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The first wiring diagram I have looked at (79) shows a cam and contacts beside the motor, but I'm not sure if its a switched earth or power.....suspect more likely its power switched, so a short on this cam will keep wipers running independant of the main stalk, and a complete failure will park them wherever they happen to be. Cam and contacts will be inside the worm drive case on the wiper motor.
jp 83 Euro S AT 49k
jp 83 Euro S AT 49k
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jp,
Yes I believe it is does maintain 12v to the motor during the cycle. The ground side is always grounded. You are right this interlock failing (closed) would cause the wipers to always run. This means ALWAYS RUN!though - all the time whenever the car is on... the symptoms RDS described seems to be that the switch started the wipers but that somehow they went off again (ignition?) (else how would you know it was the switch....).
If the interlock was indeed shorted youd get tirted of the wipers really fast - probbaly end up with some nice marks in the windshield too.....pretty undrivable?
RDS - relay removal fix it?
Alan
Yes I believe it is does maintain 12v to the motor during the cycle. The ground side is always grounded. You are right this interlock failing (closed) would cause the wipers to always run. This means ALWAYS RUN!though - all the time whenever the car is on... the symptoms RDS described seems to be that the switch started the wipers but that somehow they went off again (ignition?) (else how would you know it was the switch....).
If the interlock was indeed shorted youd get tirted of the wipers really fast - probbaly end up with some nice marks in the windshield too.....pretty undrivable?
RDS - relay removal fix it?
Alan
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From: Australia
Elsewhere in this thread it is said that the relay ONLY handles the intermittent and 3 wipes with wash - borne out by wiring diagram, so pulling the relay wont help. The continuous running will only be bypassed by pulling the fuse, or fixing the problem. The wrong park position is easier to live with....
jp 83 Euro S AT 49k
jp 83 Euro S AT 49k